Sub-surface plastic mulching reduced evaporation during the fallow season and increased spring maize yield in the North China Plain

Abstract

Drought stress is the main limiting factor to spring maize production in the North China Plain (NCP). However, amounts of soil water and precipitation evaporate unproductively during the long fallow season before sowing spring maize. Therefore, sub-surface plastic mulching (PM) and straw mulching (SM) were conducted to reduce evaporation following the harvest of the previous season’s crop in this three-year study. PM resulted in less water evaporation during the fallow season compared with SM and the control without mulching (CK). Thus, more water was stored in the soil under PM. Similarly, evapotranspiration from sowing to the sixth-leaf stage (V6) in CK and SM was increased by 18.5–43.1% compared with PM. Conversely, evapotranspiration of PM was higher than that of CK and SM during the V6-silking period. During the grain filling stage, there was no significant difference in evapotranspiration among treatments owing to abundant rainfall. Correlation analysis indicated that excessive soil water used during the fallow season and seedling stage exacerbated the yield reduction. However, more water employed from V6 to silking increased yield. PM increased soil temperature during the seedling stage, thus accelerating spring maize growth, but without significantly affecting grain yield. PM could increase leaf area index, thus improving the biomass accumulation. Finally, the kernel setting rate was elevated under PM compared to CK and SM. Grain yield, water use efficiency (WUE), and annual WUE of PM were increased by 9.3–15.2%, 8.7–15.6%, and 16.7–25.8% relative to CK and SM, respectively. In conclusion, sub-surface plastic mulching stored water for spring maize growth and development, and enhanced water availability during the critical stage of water demand, thus increasing grain yield and WUE and reducing annual evapotranspiration.